1. Field of the Invention
The present invention relates to an optical coherence tomographic apparatus, a control method for the optical coherence tomographic apparatus, and a storage medium.
2. Description of the Related Art
Currently, optical coherence tomographic apparatuses based on OCT (Optical Coherence Tomography) using multiwavelength light wave coherence are known. For example, such apparatuses are used to obtain organ information with an endoscope and retina information in an ophthalmic apparatus. The application field of these apparatuses to the human bodies has become more and more broad. An optical coherence tomographic apparatus applied to the eyes is becoming indispensable in outpatient clinics specialized in retinas as an ophthalmic apparatus.
Such an optical coherence tomographic apparatus is an apparatus which performs measurement by irradiating a sample with measurement light which is low-coherent light, and by using backscattered light from the sample for an interference system. Irradiating one point on a sample with measurement light can obtain image information in the depth direction at the point on the sample. In addition, performing measurement while scanning measurement light on a sample can obtain a tomographic image of the sample. When applying this apparatus to the fundus, it is possible to capture a tomographic image of the fundus of the eye to be examined at high resolution by scanning measurement light on the fundus of the eye. For this reason, these apparatuses are widely used for ophthalmic diagnosis of the retinas and the like.
Optical coherence tomographic apparatuses generally use an imaging method of obtaining a plurality of tomographic images by reciprocally scanning on the fundus as a measurement target in the horizontal or vertical direction. For example, it is possible to obtain one high-quality fundus tomographic image by obtaining a plurality of fundus tomographic images of the same region by performing scanning on the same region on the fundus a plurality of times and performing averaging processing of the obtained images. It is also possible to obtain a three-dimensional image of the fundus by performing scanning a plurality of times while translating the scan position. When, however, performing scanning a plurality of times in this manner, it takes a certain period of time to complete the imaging operation. For this reason, the eye may move during the operation.
In contrast to this, according to the ophthalmic imaging apparatus disclosed in Japanese Patent Laid-Open No. 2008-29467, there is disclosed a method (fundus tracking) of sequentially capturing front images of the eye to be examined, detecting the movement of the eye by using a plurality of obtained front images, and correcting the scan position in accordance with the detected movement of the eye. As described above, it is important for the optical coherence tomographic apparatus to perform the processing of reducing the influence of the movement of the eye.
On the other hand, it is important for the optical coherence tomographic apparatus to keep the positional relationship between the eye to be examined and the apparatus main body constant. In order to obtain a high-quality fundus tomographic image, it is necessary to match the imaging optical axis of the optical coherence tomographic apparatus with the pupil position of the eye to be examined and to adjust the relative positions of the imaging optical system and the eye to be examined so as to make imaging light fall within the pupil.
In contrast to this, according to the ophthalmic apparatus disclosed in Japanese Patent No. 4354601, there is disclosed an automatic alignment mechanism for automatically adjusting the relative positional relationship between the eye to be examined and an optical storage portion.